JP2000030270A - Optical disk device and its control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system, capable of generating an optimum synchronizing signal as a reference for generating optimum timing to start writing in data and a data reproducing clock in an optical disk device for recording/reproducing with respect to DVD-RAM of a wobbled land/groove system. SOLUTION: A synchronizing signal is generated at detection timing of a header area to be detected from a signal obtd. by amplifying an output of a photodetecting means 2, and the data on an optical disk are recorded or reproduced by this generated header synchronizing signal. As a header detection means, a header rough detection means which is plural header detection means different in detective conditions is used a header front edge detection means and the others (system using wobble detection) are provided beforehand, and the quality of the detected result of the header area by respective detection means is judged, and by selecting an optimum header detection system based on the judged result, the precise header synchronizing signal is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical disk device such as a DVD-RAM drive capable of recording / reproducing data and a control circuit therefor.

[0002]

2. Description of the Related Art A wobble land / groove system is adopted as a physical format of a DVD-RAM. In the wobble land-groove method, as shown in FIGS. 8 and 9, a convex track (groove track) 100 formed on the disk surface is viewed from the side irradiated with the laser beam.
This is a method in which marks are recorded on both tracks of the track 101 and the concave track (land track) 101. A minute undulation called a wobble 102 is formed on a track at a predetermined frequency, and a rough read channel PLL pull-in can be performed based on a frequency signal obtained by detecting the wobble 102. I have.

[0003] A DVD-RAM is provided with a header section 105 arranged so as to cut the land track 101 and the groove track 100. In the header section 105, bits as address information are recorded at the time of manufacture. I have. That is, in the wobble land / groove method, an address can be detected by reading bits of the header section 105.

[0004] However, the header portion also disturbs the physical continuity of the land track and the groove track. The influence is exerted on a tracking servo and a focus servo executed based on a signal detected by a photodetector of the optical pickup. For these controls, the light detection signal obtained from the header portion acts as noise, causing problems such as servo disturbance, misreading of address information, and occurrence of unnecessary track jumps.

[0005]

SUMMARY OF THE INVENTION
In a disk drive for recording / reproducing a land-groove type DVD-RAM, it is necessary to generate an accurate timing for starting to write data to the disk. How to generate a synchronization signal as a reference for generating this timing Is one of the issues to be considered in product development. Further, there is a demand for an optimal method for obtaining a synchronization signal serving as a reference for generating a reproduction clock when reproducing data from a disk.

Accordingly, the present invention provides an optical disc apparatus for recording / reproducing a wobble / land-groove DVD-RAM, which is an optimal timing for starting data writing and an optimal timing serving as a reference for generating a clock for data reproduction. It is an object of the present invention to provide a method capable of generating a synchronization signal.

Another object of the present invention is to provide an optical disk apparatus and a control circuit for the optical disk apparatus, which can more accurately identify a header area and a data area in a land / groove type disk.

[0008]

In order to achieve the above object, an optical disk apparatus according to the present invention comprises a header area in which address data is recorded in advance and a recording area for a user. An optical disc apparatus for recording or reproducing data on or from an optical disc having a light beam irradiating means for irradiating the optical disc with a light beam to form a light beam spot; and receiving light reflected by the optical beam spot from the optical disc. Optical detection means for optically reading the data in the header area and the recording area and outputting the data as an electric signal; preamplifying means for amplifying the output of the light detecting means; and the header from the output of the preamplifying means. Header detection means for detecting an area, and a header synchronization signal synchronized with the output from the header detection means. A header sync signal generating means for forming,
Means for recording or reproducing data on or from the optical disk using a header synchronization signal generated by the header signal generation means.

According to a second aspect of the present invention, there is provided the optical disk apparatus according to the first aspect, wherein the wobble detecting means detects a wobble from an output of the preamplifier, and Wobble synchronization signal generation means for generating a wobble synchronization signal synchronized with the output from the detection means, wherein the header synchronization signal generation means is generated by the output of the header detection means and the wobble synchronization signal generation means. And generating the header detection synchronization signal based on the wobble synchronization signal.

According to a third aspect of the present invention, there is provided an optical disk device according to the first or second aspect, wherein the header detecting unit includes a plurality of header detecting units having different detection conditions. Means for judging the quality of the detection result of the header area by each of the header detection means, and selecting an optimum header detection means from the plurality of header detection means based on the judgment result. And

Further, according to a fourth aspect of the present invention, in the optical disk device according to the first aspect, based on the header synchronization signal generated by the header synchronization signal generating means, The apparatus further comprises means for setting an effective section for detecting the header area from an output of the preamplifier.

According to the present invention, a synchronization signal is generated from the detection timing of the header area detected from the signal obtained by amplifying the output of the light detection means, and the recording or reproduction of data on or from the optical disk is performed using the generated header synchronization signal. I do. Also, a plurality of header detection means having different detection conditions are provided as means for detecting the header area, and the quality of the detection result of the header area by each detection means is determined. Based on the determination result, a plurality of header detections are performed. By selecting the optimum header detecting means from the means, a more accurate header synchronization signal can be obtained, and the reliability can be improved.

A wobble detecting means for detecting a wobble from the output of the preamplifying means is provided. A wobble synchronizing signal synchronized with the wobble detecting signal is generated from the output of the wobble detecting means. By generating a header detection synchronization signal based on
An even more accurate header synchronization signal can be obtained. Further, by setting an effective section for detecting the header area from the output of the preamplifier based on the header synchronization signal generated by the header synchronization signal generation means, the header area is affected by noise and the like other than the header area. The probability of erroneous detection is reduced, and further improvement in accuracy can be expected.

This makes it possible to generate an optimum timing for starting data writing and an optimum synchronization signal as a reference for generating a clock for data reproduction. Can be identified more accurately.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a DVD-RAM drive as an optical disk device according to one embodiment of the present invention. Note that the “... Means” described below is provided by, for example, a chip or another circuit mounted on a substrate.

The reflected light of the laser radiated from the optical pickup to the optical disk 1 which is a DVD-RAM medium is input to the light detecting means 2 in the optical pickup, where it is converted into an electric signal. Amplified by The amplified signal 21 is input to the tracking error signal generator 4, the focus error signal generator 5, the header leading edge detector 6, the header rough detector 7, and the wobble detector 8, respectively.

The tracking error signal generating means 4 extracts the tracking error information contained in the amplified signal 21 and outputs it as a tracking error signal 22. The tracking error signal 22 is input to the changeover switch 9 and the tracking error signal holding means 10, respectively.

The tracking error signal holding means 10 holds the value of the tracking error signal 22 at the timing of starting input of the tracking error holding switching control signal 24 given from the control means 20. The changeover switch 9 is
Based on the tracking error holding switching control signal 24 given from the control means 20, either the output of the tracking error signal generating means 4 or the output of the tracking error signal holding means 10 is selected and output to the tracking servo control means 11.

Based on the tracking error signal selected by the changeover switch 9, the tracking servo control means 11 adjusts the light spot of the laser beam emitted by the light detection means 2 along a track (land track or groove track) on the optical disc 1. The position of the optical pickup having the light detecting means 2 in the disk radial direction is controlled so that the optical pickup moves.

The control means 20 immediately before entering the section where the characteristic desired as the tracking error signal 22 is interrupted due to the structure of the signal recording surface of the DVD-RAM medium (the section where the light spot passes through the header area in FIGS. 8 and 9). The value of the tracking error signal 22 is held by the tracking error signal holding means 10, the output of the tracking error signal holding means 10 is selected by the changeover switch 9 in that section, and the output of the tracking error signal generating means 4 is selected in other sections. The tracking error holding switching control signal 24 is selected to
Is output.

The focus error signal generating means 5 extracts focus error information contained in the amplified signal 21 and outputs it as a focus error signal 23. The focus error signal 23 is input to the changeover switch 12 and the focus error signal holding means 13, respectively.

The focus error signal holding means 13 holds the value of the focus error signal 23 at the timing when the input of the focus error holding switching control signal 25 given from the control means 20 is started. The changeover switch 12 controls the focus error signal generator 5 based on the focus error holding switch control signal 25 given from the controller 20.
And the output of the focus error signal holding means 13 is selected and output to the focus servo control means 14.

The focus servo control means 14 controls the light detection means based on the signal selected by the changeover switch 12 so that the disk surface on the optical disk 1 is positioned within the beam waist of the laser beam irradiated by the light detection means 2. 2 is controlled in the focus direction.

The control means 20 immediately before the section where the characteristic desired as the focus error signal 23 is interrupted due to the structure of the signal recording surface of the DVD-RAM medium (the section where the light spot passes through the header area in FIGS. 8 and 9). The focus error signal holding unit 13 holds the value of the focus error signal 23,
The focus error holding switching control signal 25 is output so that the output of the focus error signal generation means 5 is selected in other sections.

The header leading edge detecting means 6 extracts header leading edge position information from the input amplified signal 21 and detects a header leading edge position which is a pulse having a fixed time width representing the header leading edge position information. The signal 26 is output to the header detection selection means 15 and the control means 20. The control means 20 inputs a header detection selection control signal 32 which is a pulse having a certain time width to the header detection selection means 15. The header detection selection means 15 receives the header detection selection control signal 32, masks (selects) the input header leading edge detection signal 26 with the header detection selection control signal 32, and is a pulse generated by noise or the like. The detection result that does not indicate the original header position is removed, and a leading edge detection signal 29 having improved correspondence with the original header leading edge position is output to the signal selection unit 18.

The header rough detection means 7 generates a header rough detection signal 27, which is a pulse having a fixed time width representing a rough position information of a header position that can be detected even during traversal, from the input amplified signal 21, and performs header detection. It outputs to the selection means 16 and the control means 20.

The control means 20 inputs a header detection selection control signal 33 which is a pulse having a fixed time width to the header detection selection means 16. The header detection / selection means 16 receives the header detection / selection control signal 33, masks (selects) the input header rough detection signal 27 with the header detection / selection control signal 33, and outputs a pulse generated by noise or the like. The detection result that does not indicate the header position is removed, and a header rough detection signal 30 having improved correspondence with the original header position is output to the signal selection unit 18. The wobble detection means 8 receives the amplified signal 21, extracts a wobble component included in the amplified signal 21 when a track of the optical disc 1 includes a wobble, and outputs the wobble detection signal 28. The wobble detection signal 28 is input to the wobble synchronization signal generation means 17 and the wobble synchronization signal 31 obtained by interpolating the omission of the wobble detection signal 28 is output to the signal selection means 18
To enter.

The control means 20 inputs the header leading edge detection means 6, the header rough detection means 7,
A signal selection control signal 38 for selecting one or more of the wobble detection means 8 and other inputs.
Is input to the signal selection means 18. The signal selector 18 outputs the selected signal 35 to the header detection synchronization signal generator 19. The header detection synchronization signal generation means 19 outputs a signal 36 synchronized with the input signal 35 to the control means 20.

The header detection synchronizing signal generation means 19 has a plurality of different gains determined in advance, and selects a gain according to a gain selection control signal 37 output from the control means 20.

The header detection synchronization signal generation means 19 detects a phase difference and a period difference between the signal 35 input from the signal selection means 18 and the output signal 36, and based on the synchronization method selection control signal 34 output from the control means 20. The input signal 35 and the output signal 36 are synchronized by selectively using the phase difference information or the period difference information.

The control means 20 predicts a header area based on the input synchronization signal 36, and at a timing immediately before the header area determined from the predicted header position, the tracking error signal holding switching control signal 24 and the focus error signal. By outputting the holding switching control signal 25, the tracking error signal holding means 10 holds the value of the tracking error signal immediately before the header area, and the focus error signal holding means 13 causes the focus error signal immediately before the header area to be held. The error signal is held. As a result, the tracking servo and the focus servo are not affected by the header area, and stable tracking servo and focus servo can be maintained.

Further, the control means 20 generates a header rough detection selection control signal 33 having a fixed time width based on the predicted header position in order to enhance the quality of the header rough detection signal 27. The control means 20 determines whether or not the input header rough detection signal 27 is within the time width indicated by the header rough detection selection control signal 33 generated based on the predicted header position. Is determined based on the number of times the header leading edge detection signal 26 does not continuously enter the header rough detection status. Then, the control unit 20 optimally changes the time width indicated by the header rough detection selection control signal 33 according to the quality of the determined header rough detection status.

Further, the control means 20 determines the quality of the header leading edge detection signal 26 and selects a header leading edge detection signal having a fixed time width, which serves as means for preventing the influence of erroneous detection and improving detection accuracy. A control signal 32 is generated and output based on the predicted header position. The control means 20 determines whether or not the header leading edge detection signal 26 is within the time width indicated by the detection selection control signal 32, and determines whether the header leading edge detection status is good or not based on the number of times. For example, the quality of the header leading edge detection status is determined from the number of times that the header rough detection signal 27 has not been continuously input within the time width. Then, the control unit 20 optimally changes the time width indicated by the header leading edge detection selection control signal 32 according to the quality of the determined header leading edge detection status.

The control means 20 outputs a gain selection control signal 37 and a synchronization method selection control signal 34 according to the quality of the header rough detection state and the header leading edge detection state, thereby selecting a synchronization method according to the detection state. I do.

The control means 20 outputs a signal selection control signal 38 to the signal selection means 18 in accordance with whether the header rough detection state and the header leading edge detection state are good or bad, so that the most reliable under the current detection state. Then, a synchronization signal 36 is created by selecting a header detection signal.

Here, the control means 20 masks the header itself detected from the header position signal with the header leading edge detection selection control signal 32 and the header rough detection selection control signal 33. The header that appears next to the header detected from the header position signal is masked. The header is masked at each output timing of the header detection synchronizing signal generation means 19. And output using any of the methods.

The output 36 of the header detection synchronizing signal generation means 19 is passed to the post-processing means, and is used for, for example, generating a timing for pulling in the read channel PLL and generating a start timing for writing data to the disk. Is done.

Next, the operation of the present embodiment will be described with reference to FIGS. 2 to 5 by taking as an example the case where a header detection synchronization signal is generated from each output of the header leading edge detection means 6, the header rough detection means 7 and the wobble detection means 8. This will be described with reference to FIG.

First, in FIG. 2, the control means 20 sends the signal selection control signal 38 to the signal selection means 18 so as to select the output of the spindle FG detection means 41 for detecting the rotation speed of the spindle motor 39 for driving the optical disk. Input (step 201). Spindle FG detection means 41
Generates a signal 42 corresponding to the header interval determined according to the current disk radial position from the FG output 40 of the spindle motor 39. The frequency-divided signal 42 is directly provided to the control means 20 (step 202).

Here, the control means 20 determines whether or not the disk rotation speed is within a predetermined range based on the header synchronization signal 36 of the input FG frequency division signal 42 (step 20).
3) If not, return to step 202 and execute FG
The generation of the header synchronization signal 36 from the frequency-divided signal 42 (35) is continued.

If the disk rotation speed is within the predetermined range, the control means 20 outputs the output of the header rough detection means 7 (the output of the header detection selection means 16) in FIG.
Is selected, the signal selection control signal 38 is input to the signal selection means 18 (step 301). The header rough detection unit 7 detects the amplified signal 21 of the signal detected by the light detection unit 2 during the traverse (when the tracking servo is OF).
A header rough detection signal 27 having a fixed time width representing rough position information of a header position that can be detected even in the F state) is generated.

The header detection by the header rough detection means 7 and the header leading edge detection means 6 is performed by detecting the header components appearing in the output waveform of the light detection means 2 according to respective predetermined standards.

The header rough detection signal 27 output from the header rough detection means 7 is input to the header detection and selection means 16 and is converted into a pulse-shaped header rough detection signal 30 from which noise and the like are removed and which indicates the header position with high quality. The signal is output to the signal selecting means 18. This header rough detection signal 3
0 is input to the header detection synchronization signal generation unit 19 through the signal selection unit 18 and the header detection synchronization signal generation unit 1
9 is based on the input header rough detection signal 30 (35).
A header synchronizing signal 36 synchronizing with this is generated (step 302), and given to the control means 20.

Here, the control means 20 generates each timing of the tracking error signal holding switching control signal 24 and the focus error signal holding switching control signal 25 based on the input header synchronization signal 36 (step 30).
3). That is, the control means 20 outputs the tracking error signal holding switching control signal 24 and the focus error signal holding switching control signal 25 at the timing immediately before the predicted header position with reference to the header synchronization signal 36, so that the immediately preceding header position is output. Control is performed such that the tracking error signal holding means 10 and the focus error signal holding means 13 hold the tracking error signal and the focus error signal.

Next, the control means 20 outputs the header synchronization signal 36
, And outputs the header detection selection control signals 32 and 33 to the header detection selection means 15 and 16 as a protection window for noise removal and the like, and uses the header detection selection signals 15 and 16 to confirm the reliability of the header detection. Then, a header arrival detection window is generated (step 304). The header arrival detection window and the protection window are both set within the range including the header position from the same header synchronization signal 36, but the lengths and positions of both may or may not match.

Subsequently, in step 305, the control means 20 superimposes the header rough detection signal 27 directly fetched from the header rough detection means 7 and the generated header arrival detection window on the time axis, and Is included in the header arrival detection window. As a result of this determination, if the header arrival detection window in which the header rough detection signal 27 does not enter is continuously generated a predetermined number of times (for example, three times) (step 305), the step 2 shown in FIG.
01, and the output of the signal selecting means 18 is set to the spindle FG.
The output is switched to the output of the detecting means 41. Also, as a result of the above-described determination, when the header arrival detection window in which the header rough detection signal 27 does not enter is continuously generated a predetermined number of times (for example, three times) (step 306), the process proceeds to step 401 shown in FIG. In other cases, the process returns to step 302 in FIG. 3 to continue the above-described header rough detection.

In step 401 of FIG. 4, the control means 20 controls the signal selection control signal 3 so as to select the output of the header leading edge detection means 6 (the output of the header detection selection means 15).
8 is input to the signal selecting means 18 (step 401).
The header leading edge detecting means 6 detects the tracking servo ON from the amplified signal 21 of the signal detected by the light detecting means 2.
A header leading edge detection signal 29 having a fixed time width representing information on a header position that can be detected at the time of (1) is generated. When the tracking servo is ON, that is, when the fluctuation of the amplified signal 21 is relatively small (tracking servo OFF)
In a small situation (compared to the time), the threshold is set using a threshold set so that the waveform of the amplified signal 21 corresponding to the header position can be distinguished from the signal waveform at other positions.

The header leading edge detection signal 29 generated by the header leading edge detecting means 6 is
, And is output as a pulse-shaped header leading edge detection signal 29 indicating the header position with high quality, from which noise and the like have been removed, to the signal selection means 18. The header leading edge detection signal 29 is input to the header detection synchronization signal generation means 19 through the signal selection means 18, and the header detection synchronization signal generation means 19 receives the input header leading edge detection signal 29 (3
From 5), a header synchronization signal 36 synchronized with this is generated (step 402) and given to the control means 20.

Here, the control means 20 generates each timing of the tracking error signal holding switching control signal 24 and the focus error signal holding switching control signal 25 based on the input header synchronization signal 36 as in the case of detecting the header rough. (Step 403). That is, the control means 20 outputs the tracking error signal holding switching control signal 24 and the focus error signal holding switching control signal 25 at the timing immediately before the predicted header position with reference to the header synchronization signal 36, so that the immediately preceding header position is output. Control is performed such that the tracking error signal holding means 10 and the focus error signal holding means 13 hold the tracking error signal and the focus error signal.

Next, the control means 20 generates the header detection selection control signals 32 and 33 based on the header synchronization signal 36 as in the case of the header rough detection, and
The headers 5 and 16 are output as protection windows for noise removal and the like, and a header arrival detection window used for confirming the reliability of the header leading edge detection is generated (step 404).

Subsequently, in step 405, the control means 20 superimposes the header leading edge detection signal 26 directly fetched from the header leading edge detecting means 6 and the generated header arrival detection window on the time axis. It is determined whether the header leading edge detection signal 26 is within the header arrival detection window. As a result of this determination, if the header arrival detection window in which the header leading edge detection signal 26 does not enter is continuously generated a predetermined number of times (for example, three times) (step 305), step 3 shown in FIG.
Returning to 01, the output of the signal selection means 18 is switched to the output of the header rough detection means 7. Also, as a result of the above judgment,
When the header arrival detection window in which the header leading edge detection signal 26 does not enter is continuously generated a predetermined number of times (for example, three times) (step 406), the process proceeds to step 501 shown in FIG. In other cases, the process returns to step 402 in FIG. 4, and the above-described header leading edge detection is continued.

In step 501 of FIG. 5, the control means 20 outputs the signal selection control signal 38 so as to select the output of the wobble detection means 8 together with the output of the header leading edge detection means 6 (the output of the header detection selection means 15). Signal selection means 1
Enter 8

The header leading edge detection signal 29 generated by the header leading edge detecting means 6 (header detecting / selecting means 15) is input to the header detecting / selecting means 15, where the header position from which noise or the like has been removed is converted to a high quality. Is output to the signal selection means 18 as a pulse-like header leading edge detection signal 29, and the wobble detection signal 28 generated by the wobble detection means 8 is input to the wobble synchronization signal generation means 17, where A wobble synchronization signal 31 obtained by interpolating the omission of the wobble detection signal 28 is input to the signal selection unit 18.

The header leading edge detection signal 29 and the wobble synchronization signal 31 selected by the signal selection means 18 are input to the header detection synchronization signal generation means 19, and the header detection synchronization signal generation means 19 receives the input header leading edge detection signal. 29 and the wobble synchronizing signal 31 (35), a header synchronizing signal 36 synchronizing therewith is generated (step 501).
Give to 0.

The control means 20 controls the tracking error signal hold switching control signal 24 and the tracking error signal holding signal 29 and 35 based on the input header leading edge detection signal 29 and the wobble synchronization signal 31 (35) in the same manner as in the header rough detection and the header leading edge detection. Each timing of the focus error signal holding switching control signal 25 is generated (step 502).

Next, the control means 20 controls the header detection selection control signal 32 based on the input header leading edge detection signal 29 and the wobble synchronization signal 31 (35) in the same manner as in the header rough detection and the header leading edge detection. , 33 are output to the header detection selecting means 15 and 16 as a protection window for noise removal and the like, and a header arrival detection window used for confirming the reliability of the header position detection is generated. (Step 503).

Subsequently, in step 504, the control means 20 superimposes the header leading edge detection signal 26 directly fetched from the header leading edge detecting means 6 and the generated header arrival detection window on the time axis. It is determined whether the header leading edge detection signal 26 is within the header arrival detection window. As a result of this determination, if the header arrival detection window in which the header leading edge detection signal 26 does not enter is continuously generated a predetermined number of times (for example, three times) (step 504), the process proceeds to step 4 shown in FIG.
Returning to 01, the output of the signal selecting means 18 is switched to the output of only the header leading edge detecting means 6. Otherwise, see FIG.
Returning to step 501, the above-described header leading edge detection and wobble detection are continued.

FIG. 6 shows the effect of the header area on the tracking error signal and the focus error signal in comparison between the conventional case and the present embodiment. In this embodiment,
The signal immediately before the header area is held, and in the header area section, tracking control or focus control is performed based on the held tracking error signal or focus error signal. The tracking servo and the focus servo can be maintained stably.

As shown in FIG. 7, the header detection synchronizing signal generating means 19 converts the header synchronizing signal 35 obtained by the header leading edge detecting means 6, the header rough detecting means 7, the wobble detecting means 8 and others. The synchronization signal 36 is generated, and based on the header synchronization signal 36, the output of the focus error holding means is selected during the header area period, and the output of the focus error signal generation means is selected during the non-header area period. In addition, it is less susceptible to the detection failure of the header area due to a scratch on the disc, and the reproduction quality can be improved.

[0061]

As described above, according to the present invention, it is possible to generate an optimum timing for starting data writing and an optimum synchronization signal as a reference for generating a clock for data reproduction. . Also, a plurality of header detection means having different detection conditions are provided as means for detecting the header area, and the quality of the detection result of the header area by each detection means is determined. Based on the determination result, a plurality of header detections are performed. By selecting the optimum header detecting means from the means, a more accurate header synchronization signal can be obtained, and the reliability can be improved. Further, a wobble detecting means for detecting a wobble from the output of the preamplifier is provided, a wobble synchronizing signal synchronized with the wobble detecting signal is generated from the output of the wobble detecting means, and a header is generated based on the output of the header detecting means and the wobble synchronizing signal. By generating the detection synchronization signal, a more accurate header synchronization signal can be obtained. Further, by setting an effective section for detecting the header area from the output of the preamplifier based on the header synchronization signal generated by the header synchronization signal generation means, the header area is affected by noise and the like other than the header area. The probability of erroneous detection is reduced, and further improvement in accuracy can be expected.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a DVD-RAM drive as an optical disk device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure for detecting a header synchronization signal in the DVD-RAM drive of the embodiment shown in FIG. 1, and is a flowchart showing an operation immediately after the start of disk rotation.

FIG. 3 is a flowchart showing a procedure of detecting a header synchronization signal in the DVD-RAM drive of the embodiment shown in FIG. 1, and is a flowchart showing an operation of detecting a header rough.

4 is a flowchart showing a procedure for detecting a header synchronization signal in the DVD-RAM drive of the embodiment shown in FIG. 1, and is a flowchart showing an operation of detecting a header leading edge.

5 is a flowchart showing a procedure for detecting a header synchronization signal in the DVD-RAM drive of the embodiment shown in FIG. 1, and is a flowchart showing a procedure for generating a header synchronization signal based on header leading edge detection and wobble detection.

FIG. 6 is a diagram comparing the influence of a header area on a tracking error signal and a focus error signal between a conventional case and the present embodiment.

FIG. 7 is a diagram showing a synchronization signal of a header detection signal.

FIG. 8 is a diagram showing a physical format of a DVD-RAM.

FIG. 9 is a diagram showing a configuration of a header section in the physical format of the DVD-RAM of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... Light detection means 3 ... Preamplification means 4 ... Tracking error signal generation means 5 ... Focus error signal generation means 6 ... Header leading edge detection means 7 ... · Header rough detection means 8 · · · Wobble detection means 9 and 12 · · · Changeover switch 10 · · · tracking error signal holding means 11 · · · tracking servo control means 13 · · · focus error signal holding means 14 · · ·. · Focus servo control means 15 ··· Header detection selection means 16 ··· Header detection selection means 17 ··· Wobble synchronization signal generation means 18 ··· Signal selection means 19 ··· Header detection synchronization signal generation means 20 ··· .Control means

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yo Yoshioka 3-3-9, Shimbashi, Minato-ku, Tokyo F-term in Toshiba Abu E Co., Ltd. 5D044 BC04 BC06 CC06 DE03 DE32 DE38 GM03 JJ01 JJ02 5D090 AA01 BB04 CC01 CC04 DD03 EE15 FF07 GG03 GG07 GG26 GG27 5D118 AA11 BA01 BB02 BC08 BC09 BF02 BF03 CA00 CC12 CD07 CD08

Claims (8)

[Claims] 1. An optical disk apparatus for recording or reproducing data on an optical disk having a header area in which address data is recorded in advance and a recording area for a user, wherein the optical disk is irradiated with a light beam to form a light beam spot. A light beam irradiating unit that receives light reflected from the optical disk of the light beam spot, optically reads data in the header area and the recording area, and outputs the data as an electric signal; Preamplifier for amplifying the output of the preamplifier; header detection means for detecting the header area from the output of the preamplifier; and a header synchronization signal for generating a header synchronization signal synchronized with the output from the output of the header detection means. Generating means, and a header synchronization signal generated by the header signal generating means. Means for recording or reproducing data on or from the optical disk. 2. The optical disk device according to claim 1, wherein a wobble detection means for detecting a wobble from an output of said preamplifier means, and a wobble synchronization signal for generating a wobble synchronization signal synchronized with the output from said wobble detection means. And a signal generation unit. The header synchronization signal generation unit generates the header detection synchronization signal based on an output of the header detection unit and a wobble synchronization signal generated by the wobble synchronization signal generation unit. Characteristic optical disk device. 3. The optical disk device according to claim 1, wherein a plurality of header detection units having different detection conditions are used as the header detection unit, and the quality of the detection result of the header region by each of the header detection units is determined. Means for selecting an optimum header detecting means from among the plurality of header detecting means based on the result of the determination. 4. The optical disk device according to claim 1, wherein the header area is detected from an output of the preamplifier based on a header synchronization signal generated by the header synchronization signal generator. An optical disc device further comprising means for setting an effective section. 5. An optical disk device for recording or reproducing data on or from an optical disk having a header area in which address data is recorded in advance and a recording area for a user, wherein the optical disk is irradiated with a light beam to form a light beam spot. A light beam irradiating means for forming, a light detecting means for receiving the reflected light of the light beam spot from the optical disc, optically reading the data in the header area and the recording area, and outputting as an electric signal,
In a control circuit of an optical disc apparatus having a preamplifier for amplifying an output of the photodetector, a header detector for detecting the header area from an output of the preamplifier; Header synchronizing signal generating means for generating a header synchronizing signal synchronized with the optical disk; and means for transmitting the header synchronizing signal generated by the header synchronizing signal generating means to a circuit for recording or reproducing data on the optical disk. A control circuit for an optical disk device, comprising: 6. The control circuit of an optical disk device according to claim 5, wherein a wobble detecting means for detecting a wobble from an output of said preamplifier, and a wobble synchronization signal synchronized with the output from said wobble detecting means are generated. Wobble synchronization signal generation means, wherein the header synchronization signal generation means generates the header detection synchronization signal based on the output of the header detection means and the wobble synchronization signal generated by the wobble synchronization signal generation means. A control circuit for an optical disk device. 7. The control circuit for an optical disk device according to claim 5, wherein a plurality of header detection units having different detection conditions are used as the header detection unit, and whether the detection result of the header area by each of the header detection units is good or bad. And a means for selecting an optimum header detecting means from among the plurality of header detecting means based on the result of the judgment. 8. The control circuit for an optical disk device according to claim 5, wherein the header area is output from the preamplifier based on a header synchronization signal generated by the header synchronization signal generator. A control circuit for an optical disk device, further comprising: means for setting an effective section for detecting an error.